1. Field of the Invention
The present invention is related to civil structures such as a road for use in cold climates, as well as a machine and technique for constructing same. More particularly, the present invention is directed towards a method and apparatus for constructing a novel road whose principal component consists of a crushed ice aggregate.
2. Description of the Prior Art
Wintertime work in environmentally sensitive parts of the arctic and sub-arctic often requires that access roads, work pads and air strips be constructed of non-permanent materials which will not be detrimental to the underlying native vegetation.
The prior art has recognized the unique problems surrounding the construction of a suitable roadway in such cold climates. In the past, a common solution has been to construct such roads of ice. For example, the Rowley et al U.S. Pat. No. 3,986,783 teaches a method and machine for constructing ice roads upon snow-covered regions. The machine gathers snow from the region upon which the road is to be built, heats the gathered snow until it is partially melted and becomes slush, and then spreads the slush to form the road upon refreezing. Other U.S. patents of which I am aware which also relate to ice roads formed from snow include the Nokolaev et al U.S. Pat. No. 3,371,586 and the Condo et al U.S. Pat. No. 3,818,711.
However, contrary to popular opinion, in many parts of the high latitudes very little snow falls, and what does fall is not predictable and seldom remains in a uniform distribution over the land surface because of incessant transport by the wind. As a consequence, snow is often found to be an unreliable material of construction therefore severely limiting the known prior art techniques of utilizing snow to construct ice roads.
In contrast, the occurrence of sub-freezing temperatures and consequent freezing of the surfaces of lakes and rivers is highly predictable and is uniform over large regions. Ice therefore appears to be a more readily available base material from which roadways in cold climates can be constructed. Of course, it would be necessary to mine or harvest the ice preparatory to constructing the desired road. Fortunately, the technology of mining or harvesting ice was developed years ago when such ice was the primary source of refrigeration during warmer periods of the year. However, to the best of my knowledge, the use of such ice as a construction material for wintertime temporary structures such as roads or the like has, prior to my invention, not been utilized.
In a publication entitled: "Building And Operating Winter Roads In Canada And Alaska" by Kenneth M. Adam on behalf of the Canadian Department of Indian and Northern Affairs, (believed published in 1978), the author describes an aggregate ice road whose "development was inspired by Alaskan Arctic Gas Pipeline Company as a technique to protect sensitive terrain from heavy traffic in areas where a lack of snow or lack of available water precludes the use of snow roads or solid ice roads." (Page 59). The aggregate ice road described by this author is believed derived from earlier studies and experiments I had performed in Fairbanks, Alaska, on behalf of the Alaskan Arctic Gas Pipeline Company. The author in this publication describes an aggregate ice road constructed utilizing a medium-sized tractor to pull the aggregating machine, a front-end loader, several dump trucks, a medium sized crawler tractor with blade for shaping the road, and a water tanker truck with spray bar for binding the aggregate. The technique and apparatus therein described calls for mining the aggregate using a roto-tiller and then transporting the ice aggregate by front-end loaders and dump trucks to the site. The loaded trucks dump the aggregate directly on the site, whereafter the crawler tractor shapes the road to the desired width and thickness. Water trucks are then used to finish the road by sprinkling with one inch of water. The author concludes that: "After sprinkling, several hours should elapse before heavy or large numbers of vehicles are allowed on the road. This will allow time for the bonds between aggregate particles to freeze solidly before the road is opened to traffic." (Page 61).
While the foregoing article by Mr. Adam summarizes my earlier experimental work as of around March, 1977, the state of the art at that time was replete with several major disadvantages. Initially, the several large pieces of different equipments required to build the road did not lend the technique to rapid or efficient construction. Further, my field tests conducted in Fairbanks did not encompass all of the conditions likely to be encountered in the high latitudes, and, consequently, left many questions unanswered. For example, the test sections had been placed over a relatively smooth, hard subsurface. Also, although the test sections constructed during the field test had successfully withstood severe heavy equipment loading, such loading was not done until several hours had elapsed from the time of spraying. Finally, the field tests at Fairbanks had been conducted with ambient temperatures above 0.degree. F., and no actual field experience was obtained at lower temperatures (e.g., -20.degree. to -40.degree. F.).
Since the initial series of tests described above, I have further refined my technique for constructing an ice aggregate road in extremely cold (e.g., below -45.degree. F.) temperatures, and have developed an apparatus which is uniquely designed to construct a smooth ice aggregate surface over uneven terrain and which permits near immediate use of the finished surface. It is towards this end that the present invention is advanced.